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Cosolvent
In chemistry, cosolvents are substances added to a primary solvent in small amounts to increase the solubility of a poorly-soluble Chemical compound, compound. Their use is most prevalent in chemical and biological research relating to pharmaceuticals and food science, where alcohol (chemistry), alcohols are frequently used as cosolvents in water (often less than 5% by volume) to dissolve hydrophobic molecules during extraction, screening, and formulation. Cosolvents find applications also in environmental chemistry and are known as effective countermeasures against pollutant non-aqueous phase liquids,Ward, C.H., Oubre, C.L., Lowe, D.F. Surfactants and Cosolvents for NAPL Remediation A Technology Practices Manual, 1st ed. CRC Press: Boca Raton, 1999. as well as in the production of functional energy materials and synthesis of biodiesel. The topic of cosolvency has attracted attention from many theorists and practicing researchers who seek to predict the solubility of compounds usin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosolvent
In chemistry, cosolvents are substances added to a primary solvent in small amounts to increase the solubility of a poorly-soluble Chemical compound, compound. Their use is most prevalent in chemical and biological research relating to pharmaceuticals and food science, where alcohol (chemistry), alcohols are frequently used as cosolvents in water (often less than 5% by volume) to dissolve hydrophobic molecules during extraction, screening, and formulation. Cosolvents find applications also in environmental chemistry and are known as effective countermeasures against pollutant non-aqueous phase liquids,Ward, C.H., Oubre, C.L., Lowe, D.F. Surfactants and Cosolvents for NAPL Remediation A Technology Practices Manual, 1st ed. CRC Press: Boca Raton, 1999. as well as in the production of functional energy materials and synthesis of biodiesel. The topic of cosolvency has attracted attention from many theorists and practicing researchers who seek to predict the solubility of compounds usin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solvent
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for polar molecules and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within the cell. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature. Major uses of solvents are in paints, paint removers, inks, and dry cleaning. Specific uses for organic solvents are in dry cleaning (e.g. tetrachloroethylene); as paint thinners ( toluene, turpentine); as nail polish removers and solvents of glue (acetone, methyl acetate, ethyl acetate); in spot removers ( hexane, petrol ether); in detergents ( citrus terpenes); and in perfumes (ethanol). Solvents find various applications in chemical, pharmaceutical, oil, and gas industries, including in chemic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solubility
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubility of a substance in a specific solvent is generally measured as the concentration of the solute in a saturated solution, one in which no more solute can be dissolved. At this point, the two substances are said to be at the solubility equilibrium. For some solutes and solvents, there may be no such limit, in which case the two substances are said to be " miscible in all proportions" (or just "miscible"). The solute can be a solid, a liquid, or a gas, while the solvent is usually solid or liquid. Both may be pure substances, or may themselves be solutions. Gases are always miscible in all proportions, except in very extreme situations,J. de Swaan Arons and G. A. M. Diepen (1966): "Gas—Gas Equilibria". ''Journal of Chemical Physi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element is therefore not a compound. A compound can be transformed into a different substance by a chemical reaction, which may involve interactions with other substances. In this process, bonds between atoms may be broken and/or new bonds formed. There are four major types of compounds, distinguished by how the constituent atoms are bonded together. Molecular compounds are held together by covalent bonds; ionic compounds are held together by ionic bonds; intermetallic compounds are held together by metallic bonds; coordination complexes are held together by coordinate covalent bonds. Non-stoichiometric compounds form a disputed marginal case. A chemical formula specifies the number of atoms of each element in a compound molecule, using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharmaceutical
A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and relies on the science of pharmacology for continual advancement and on pharmacy for appropriate management. Drugs are classified in multiple ways. One of the key divisions is by level of control, which distinguishes prescription drugs (those that a pharmacist dispenses only on the order of a physician, physician assistant, or qualified nurse) from over-the-counter drugs (those that consumers can order for themselves). Another key distinction is between traditional small molecule drugs, usually derived from chemical synthesis, and biopharmaceuticals, which include recombinant proteins, vaccines, blood products used therapeutically (such as IVIG), gene therapy, monoclonal antibodies and cell therapy (for instance, stem cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcohol (chemistry)
In chemistry, an alcohol is a type of organic compound that carries at least one hydroxyl () functional group bound to a saturated carbon atom. The term ''alcohol'' originally referred to the primary alcohol ethanol (ethyl alcohol), which is used as a drug and is the main alcohol present in alcoholic drinks. An important class of alcohols, of which methanol and ethanol are the simplest examples, includes all compounds which conform to the general formula . Simple monoalcohols that are the subject of this article include primary (), secondary () and tertiary () alcohols. The suffix ''-ol'' appears in the IUPAC chemical name of all substances where the hydroxyl group is the functional group with the highest priority. When a higher priority group is present in the compound, the prefix ''hydroxy-'' is used in its IUPAC name. The suffix ''-ol'' in non-IUPAC names (such as paracetamol or cholesterol) also typically indicates that the substance is an alcohol. However, some comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transesterification Biofuels
In organic chemistry, transesterification is the process of exchanging the organic group R″ of an ester with the organic group R' of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst. The reaction can also be accomplished with the help of other enzymes, particularly lipases (one example is the lipase E.C.3.1.1.3). Strong acids catalyse the reaction by donating a proton to the carbonyl group, thus making it a more potent electrophile, whereas bases catalyse the reaction by removing a proton from the alcohol, thus making it more nucleophilic. If the alcohol produced by the reaction can be separated from the reactants by distillation this will drive the equilibrium toward the products, this means that esters with larger alkoxy groups can be made from methyl or ethyl esters in high purity by heating the mixture of ester, acid/base, and large alcohol. Mechanism In the transesterification mechanism, the carbonyl carbon of the starting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
